In recent years, considerable advances have been made in photovoltaic (PV) cells or the like for directly converting solar energy into useful electrical energy. Typically, a plurality of these photovoltaic cells are encased between a transparent sheet (e.g. glass, plastic, etc.) and a sheet of backing material, to thereby form a flat, typically rectangular-shaped solar module (sometimes also called “laminate” or “panel”) of a manageable size (e.g. 1 meter by 2 meters). The PV cells may be made from wafers of silicon or other suitable semiconductor material, or they can be a thin film type of cell typically deposited on the substrate or backing sheet by various processes well known in the solar module art. This is the type of solar module that can be installed onto the roof of an existing structure (e.g. a house, building, or the like) to provide all or at least a portion of the electrical energy used by that structure.
Each solar module may contain any number of individual PV cells (e.g. from 1 to about 100), each of which has a positive and a negative output which, in turn, are electrically connected in series to a common positive and negative bus bar or output wire, respectively, to produce the desired voltage from the module as will be understood in the art. The terminals of the positive and negative outputs typically pass through the backing material near one end of the module. The respective outputs can pass directly through the backing material or as is more likely, will be connected through a PC board within the solar module (e.g. a PC board having components which allow the module to continue to function when one or more individual PV cell becomes inoperable for any reason).
Once the positive and negative outputs are soldered onto the outside of a module, they must then be connected to respective positive and negative output cables which, in turn, convey the electric current from the module so the current can be used for its intended purpose. Typically, one end of each of the cables is soldered to an output terminal on the modules. A problem arises in protecting the soldered connections between the terminals and the output cables in that, if left exposed, can short out or otherwise be damaged by adverse weather or atmospheric conditions.
To protect these connections against the “elements”, a protective structure, commonly called a “junction box”, is positioned and secured over the connections and the box is filled with an epoxy to cover the connections. While previously known junction boxes have functioned well for this purpose, they have some drawbacks. For example, the epoxy is filled into the box through a small hole therein after the box has been positioned over the connections. This almost always allows small amounts of air to be trapped inside the box during the filling operation. This trapped air, in turn, can allow moisture and/or water to enter the box and attack the integrity of the connections which, in turn, can render the module inoperable.
Further, the prior art boxes are relatively large in size and require large amounts of epoxy to cover the connections. Also, due to their construction and installation of these boxes, it is not unusual for the epoxy to run out from the lower edge of the box and adversely affect the esthetic quality of the finished product. Still further, the prior boxes are relatively difficult and time consuming to assemble thereby adding to the capital costs for such solar module systems. Since solar module systems are highly competitive with other sources of electricity, any savings in the costs involved can make a solar module system more attractive to potential users. Accordingly, it can be seen that a junction box which can quickly and easily be assembled over the output connections of a solar module, use less epoxy for installation, and present a clean profile once installed would be highly beneficial in the manufacture and marketing of solar modules. The present invention provides such junction box.